perf pmus: Add notion of default PMU for JSON events

JSON events created in pmu-events.c by jevents.py may not specify a
PMU they are associated with, in which case it is implied that it is
the first core PMU. Care is needed to select this for regular 'cpu',
s390 'cpum_cf' and ARMs many names as at the point the name is first
needed the core PMUs list hasn't been initialized. Add a helper in
perf_pmus to create this value, in the worst case by scanning sysfs.

v2. Add missing close if fdopendir fails.

Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Thomas Richter <tmricht@linux.ibm.com>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: James Clark <james.clark@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/r/20230623043843.4080180-1-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

1 files changed, 16 insertions, 19 deletions

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 6142e4710a2f..963c12f910c5 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -741,9 +741,11 @@ out:
 }
 
 struct pmu_add_cpu_aliases_map_data {
+	/* List being added to. */
 	struct list_head *head;
-	const char *name;
-	const char *cpu_name;
+	/* If a pmu_event lacks a given PMU the default used. */
+	char *default_pmu_name;
+	/* The PMU that we're searching for events for. */
 	struct perf_pmu *pmu;
 };
 
@@ -752,37 +754,32 @@ static int pmu_add_cpu_aliases_map_callback(const struct pmu_event *pe,
 					void *vdata)
 {
 	struct pmu_add_cpu_aliases_map_data *data = vdata;
-	const char *pname = pe->pmu ? pe->pmu : data->cpu_name;
+	const char *pname = pe->pmu ?: data->default_pmu_name;
 
-	if (data->pmu->is_uncore && pmu_uncore_alias_match(pname, data->name))
-		goto new_alias;
-
-	if (strcmp(pname, data->name))
-		return 0;
-
-new_alias:
-	/* need type casts to override 'const' */
-	__perf_pmu__new_alias(data->head, -1, (char *)pe->name, (char *)pe->desc,
-			      (char *)pe->event, pe);
+	if (!strcmp(pname, data->pmu->name) ||
+	    (data->pmu->is_uncore && pmu_uncore_alias_match(pname, data->pmu->name))) {
+		/* need type casts to override 'const' */
+		__perf_pmu__new_alias(data->head, -1, (char *)pe->name, (char *)pe->desc,
+				      (char *)pe->event, pe);
+	}
 	return 0;
 }
 
 /*
- * From the pmu_events_map, find the table of PMU events that corresponds
- * to the current running CPU. Then, add all PMU events from that table
- * as aliases.
+ * From the pmu_events_table, find the events that correspond to the given
+ * PMU and add them to the list 'head'.
  */
 void pmu_add_cpu_aliases_table(struct list_head *head, struct perf_pmu *pmu,
-			       const struct pmu_events_table *table)
+			const struct pmu_events_table *table)
 {
 	struct pmu_add_cpu_aliases_map_data data = {
 		.head = head,
-		.name = pmu->name,
-		.cpu_name = is_sysfs_pmu_core(pmu->name) ? pmu->name : "cpu",
+		.default_pmu_name = perf_pmus__default_pmu_name(),
 		.pmu = pmu,
 	};
 
 	pmu_events_table_for_each_event(table, pmu_add_cpu_aliases_map_callback, &data);
+	free(data.default_pmu_name);
 }
 
 static void pmu_add_cpu_aliases(struct list_head *head, struct perf_pmu *pmu)